Multiple position fluid pressure motor



March 10, 1953 w, POORE 2,630,786

MULTIPLE POSITION FLUID PRESSURE MOTOR Filed June 14, 1951 2SHEETS-SHEET 1 INVENTOR. WALLACE F. 'POORE @zzza ATTORNEY March 10, 1953w. F. POORE 2,630,786

MULTIPLE POSITION FLUID PRESSURE MOTOR Filed June 14, 1951 2 SHEETSSHEET2 F162 R TAF K vxgLva H/wpLr-l pogmqgls H l l 128 I30 I32 JNVENTOR.WALLACE F POORE ZwawL.

ATTORNEY Patented Mar. 10, 1 953 'MULTIPLE POSITION FLUID PRESSURE MOTORWallace F. Poore, Wilmerding, Pa., assignor to Westinghouse Air BrakeCompany, a corporation of Pennsylvania Application June 14, 1951, SerialNo. 231,557

3 Claims.

This invention relates to fluid motors andmore particularly to the typefor operating a. device to any one of a plurality of fixed positions.

One object of the invention is to provide an improved fluid motor of theabove type.

Another object of the invention is the provision of a fluid motoroperable to effect movement of a device connected thereto successivelyfrom one to another of a plurality of definite positions which may beequally or differently spaced apart, as desired.

Another object of the invention is the provision of a fluid motoroperable to effect movement of a device connected thereto from any oneof a plurality. of positions to any other of the plurality of positions.

Other objects and advantages will be apparent from the following moredetailed description of the invention.

In the accompanying drawings; Fig. l is a diagrammatic view, mainly insection, of a fluid pressure control system embodying, in verticalsection, a fluid motor constructed in accordance with one embodiment ofthe invention; and Fig. 2 is a diagrammatic view, in development form ofan operators motor control valve device show in cross-section in Fig. 1.A

Description As shownin Fig. 1 of the drawing, the reference numeral Idesignates a fluid motor, embodying the invention, for operating adevice (notv shown) which may be connected to a piston rod 2 of saidmotor. A manually operative control valve device 3 is arranged forcontrolling supply nected to and adapted to be charged through a.

pipe and passage 1 with fluid under pressure from a reservoir 6, chargedwith fluid under pressure by a fluid compressor (not shown). Containedin the chamber 5 is a rotary valv 8 cooperating with a valve seat 9 on apipe bracket casing sec v tion ill separated from the casing section 4by a gasket ll of some suitable resilient material such as rubber, thetwo casing sections being secured together by any suitable means (not iThe rotary valve 8 is adapted to be,

-; piston rod 2.

The casing 4 is provided with an upstanding portion [5 having a spindlel6 and a flange l1 through which the stem 12 projects. A cam I8 ispress-fitted on the spindle l6 and rests against the flange H. Theperiphery of cam 18 is provided with a plurality of indents (not shown)corresponding to a plurality of positions of the handle l4. Slidablymounted in a counterbore IS in the handle I4 is a plunger 20. Theplunger 20 is provided with a counterbore 2| and is yieldingly urgedinto contact with the cam l8 by a spring 22 interposed between theleft-hand end of counterbore l9 and the right-hand end of counterbore2|. Movement of the handle 14 from one position to another is resistedby the spring 22 as the right-hand end of the plunger 20. moves from oneindent to another along the periphery of the cam l8 thereby giving anoperator a sense of feeling when the handle reaches the desiredposition.

As indicated in Fig. 2 the rotary valve 8 may be positioned in any oneof thirteen positions, one of which is shown in Fig. 1 and indicated inFig. 2 as position No. 13.

Opening at the valve seat 9 are a plurality of ports and passages 23,24, 25, 26, 21,28, 29, 39, 3! and an atmospheric exhaust port 32. Withthe rotary valve 8 in position No. 13 all of these passages are open toport 32 via cavity 33 in the rotary valve and therefore vented. Each ofthese passages is connected by a pipe bearing the same numeral to thefluid motor I.

The fluid motor I comprises a center casing section 34 and twooppositely arranged but like end casing sections 35 and 36 which aresecured to opposite ends of the center casing section 34 by a pluralityof bolts 31 and nuts 38. The oasing section 34 has a bore 39 in which isslidably mounted a piston 40 connected to one end of the A bore 4!smaller than bore 39 opens through an end wall of bore 39 to threecounterbores 42, 43 and 44 of increasing diameters open to the left-handend of easing section 34 while the opposite end of bore 39 is open to acounterbore 45 of larger diameter open to the right-hand end of casingsection 34, all of .said bores and counterbores being co-axiallyarranged one with the other. A gasket ring 46 is disposed in thecounterbore 42 and is clamped between the casing section 34 and a plug4? having screwthreaded engagement with said casing section.

The casing section 35 is provided with a counterbore 48 which is coaxialwith the bore 4| and substantially larger in diameter than thecounterbore 44. slidably mounted in the counterbore 48 is a pistonmember 49 having a counterbore 50 and a plurality of stop lugs 5! formedon the end of said piston member opposite the open end of thecounterbore 50. The lugs 5| are adapted to engage the casing section 35at the left-hand end of counterbore 48 to form between the casingsection 35 and piston member 49 a chamber 52 which is open to pipe 21.The piston member 49 is provided with an opening 53 which is connectedto the counterbore 59 by a passageway 54. The pipe is connected to thecasing section and opens into the opening 53 at a point a sufficientdistance from the lefthand wall of said opening to permit movement ofthe piston member 49 in the direction of the right-hand until saidmember engages a stop surface 55 formed on the left-hand end of thecenter casing section 34 without the piston member 49 closing theopening of pipe 26 to the opening 53.

Slidably mounted in the counterbore is a piston member having acounterbore 5'1 and a plurality of stop lugs 53 formed'on the end ofsaid piston member opposite the open end of the counterbore '51. Thelugs 53 are adapted to engage the piston member 43 at the left-hand .endof the counterbore 50 to form between the piston members 49 and 58 achamber 59 which is constantly open to pipe 28 via passageway 54 andopening 53. The piston member 49 is provided with a second opening 89.The pipe 25 is connected to the casing section 35 and opens into theopening 30 at a point a sufficient distance from the left-hand wall ofsaid opening to permit movement of the piston member 49 in the directionof the right-hand until said member engages the stop surface '55 withoutclosing the opening 'oi pipe 25 into the opening 58.

The piston member 55 is provided with an opening Bl which is connectedto the counterbore 51 by a passageway 62. The length of the coredopening 6| parallel to the horizontal axis of the piston member 55 ismade sufiicient to permit movement of said member in the direction ofthe right-hand until said member engages a stop surface 33 formed on thecenter casing section 34 at the right-hand end of the counterbore 44without said member closing the communication from the opening 68 to thepassageway 62. It may be noted that the diameter of the counterbore 44is substantially the same as the outside diameter of the piston member55. Thus the'wall of the counterbore 44 may serve as a guide for theright-hand end of the piston member 55 upon said end entering saidcounterbore.

Slidably mounted in the counterbore 51 is a piston 64 having on itsright-hand side a stem 65 formed integral therewith and of sufiicientlength to slidably extend through a bore 66 in plug 41, bore 4! and intocounterbore 39, the peripheral surface of said stem being in sealing andsliding contact with the gasket ring 49. The piston 64 is provided onits left-hand side with a plurality of stop lugs 5i adapted to engagethe piston member 53 at the left-hand end of the counterbore 51 to formbetween the piston 64 and the piston member 53 a chamber 38 in constantcommunication with pipe 25 via openings 69 and 6|, and passageway 62.

The. piston 64 is retained in the counterbore 51 by a retaining member'69 having screwthreaded engagement with the piston member 56 adjacentthe right-hand end of said counterbore. The retaining member 3.9 isprovided with a bore 19 through which projects the stem 65. The diameterof the bore '19 is substantially greater than the diameter of the stem95 to permit flow of fluid under pressure to the righthand face of thepiston 64 from pipe 24 which is connected to the center casing section34 and opens into the right-hand end of the counterbore 44.

The pipe '23 is connected to the casing section 34 and opens into thecounterbore 39 adjacent its left-hand end and thereby to a chamber "Hformed between the left-hand end of counterbore 39 and the piston 40.

The casing section 35 is provided with a counterbore "l2 and a throughbore 73 each coaxial with the counterbore 39. Slidably mounted in thebore 13 is the piston rod 2, the peripheral surface of which is insealing and sliding contact with 'a gasket ring 14, disposed in acounterbore 15 coaxial with the bore 73, and clamped between thec'asing'section 36 and a plug 16 having screw-threaded engagement withsaid casing section.

iSlidably mounted in the counterbore I2 is a piston member 1'! having acounterbore i8 and a through bore 79. 'Slidably mounted in the bore 19is the piston rod 2, the peripheral surface of which is in sealing andsliding contact with a gasket ring 83 disposed in a counterbore 8!coaxial with the bore 19 and clamped between the piston member I1 and aplug 82 having screwthreaded engagement with said piston member.

The head of plug 82 is adapted to engage the casing section '36 at theright-hand end of counterbore 12 to form between the casing section 35and piston member I! a chamber 33 which is open to pipe '28. The pistonmember 1-! is provided with an opening 34 which is connected to thecounterbore 18 by a passageway '85. The pipe 29 is connected to thecasing section 36 and opens into the opening 84 at a point a suflicientdistance from the right-hand wall of said opening to permit movement ofthe piston member 71 in the direction of the left-hand until said mem-"oer engages a stop surface 86 formed on the righthand end of centercasing section 34 without the piston member 11 closing the opening ofpipe 29 to the opening 84.

Slidably mounted in the counterbore 18 is a piston member 8'! having acounterbore 88 and a through bore '89. Slidably mounted in the bore 89is the piston rod 2, the peripheral surface of which is in sealing andsliding contact with a gasket ring 90 disposed in a counterbore 9!coaxial with the bore 89 and clamped between the piston member -81 and aplug 92 having screwthreaded engagement with said piston member.

The head of plug 92 is adapted to engage the piston member '17 at theright-hand end of counterbore 18 to form between the piston members TIand 81 a chamber 93 in constant communication with pipe 29 viapassageway 85 and opening 84.

The piston member 11 i provided with a sec ond opening 94. The pipe 30is connected to the casing section 3 6 and opens into the opening 94 ata point a sufiicient distance from the righthand wall of said opening topermit movement of the piston member 11 in the direction of theleft-hand until said member engages the stop surface 85 without closingthe opening of pipe 39 to the opening 94.

The piston member 81 is provided with an opening 95 which is connectedto the counterbore 88 by a passageway 96. Thelength of the opening 95parallel to the horizontal axis of the piston member 81 is madesuflicient to permit movement of said member in the direction of theleft-hand until said member engages a stop surf-ace 91 formed on thecenter casing section 34 at the left-hand end of the counterb-ore 45Without said member closing the communication from the opening 94 to thepassageway 96. It may be noted that the diameter of the counterbore 45is substantially the same as the outside diameter of the piston member81. The wall of the counterb-ore 45 may therefore serve as a guide forthe left-hand end of the piston member 81 upon said end entering saidoounterbore.

Slidably mounted in the counterbore 88 is a piston 98 having on one sidea stem 99 formed integral therewith. The piston 98 and stem 99 areprovided with a counterbore I00 and a through bore IOI. Slidably mountedin the bore IN is the piston rod 2, the peripheral surface of i which isin sealing and sliding contact with a gasket ring I02 disposed in thecounterbore I00 and clamped between the piston 98 and a plug I03 havingscrew-threaded engagement with said piston.

The head of plug I03 is adapted to engage the piston member 81 at theright-hand end of counterbore 88 to form between the piston 98 andpiston member 81 a chamber I04 in constant communication with pipe 30,via openings 94 and 95, and passageway 96.

The stem 99 extends from the piston 98 in the direction of the bore 39and the length of the stem is such that its end terminates at thejunction of the counterbores 39 and 45 with the pistons 98, 81 and 11 inthe position in which they are shown in the drawing to serve as a stopfor the piston 40 to limit the travel thereof in the direction of theright-hand.

The piston 98 is retained in the counterbore 88 by a retaining memberI05 having screwthreaded engagement with the piston member 81 adjacentthe left-hand end of said counterbore. The retaining member I05 isprovided with a bore I06 through which projects the stem 99. Thediameter of bore I05 is substantially greater than the diameter of thestem 99 to permit flow of fluid under pressure to the left-hand face ofthe piston 98 through a chamber I01 from the pipe 3! which is connectedto the center casing sect on 34 and opens into the left-hand end of thecounterbore 45.

In order to prevent leakage of fluid under pressure between the chambers83, 93, I04. I01, H, a chamber I08 formed between plug 41 and piston 64,chambers 68, 59 and 52, the respective piston members 11, 81, 49 and 56,and pistons 98, 40 and 64 are each provided with a resilient gasket ringI09 having sealing and sliding contact with the wall of the respectivebore in which 7 it operates.

Operation In operation. let it be assumed that the storage reservoir 6is charged with fluid to some chosen pressure, such as one hundredpounds per square inch; through pipe 1, the rotary valve chamber 5 inthe control valve device 3, is likewise charged to the same pressure.Further assume that the handle I4 of the control valve device 3 occup esthe position in which it is shown in Fig. 1, and indicated as No. 13 inFig. 2. in which the cavitv 33 in the rotary valve 8 connects the pipes23. 24. 25, 26, 21, 28, 29, 30 and 3| to the exhaust port 32. In thisposition of rotary valve 8 fluid under pressure is therefore completelyvented from the fluid motor I, this position being used whenever thefluid motor is not in use, or for making any repairs to the motor.

To maintain the piston and a device (not shown), which may be connectedthereto through the piston rod 2 against a change from the positionshown in Fig. 1, due to an external force acting on the piston rod 2 inthe direction of the left-hand, the operator will turn the handle I4 ofthe control valve device 3 from position No. 13 to position No. 1.

As will be seen in Fig. 2, with the operating handle I4 of the controlvalve device 3 in position No. 1, a cavity I I0 in the rotary valve 8connects the pipes and passages 24, 25, 26, 21, 28, 29, 30 and 3I to theexhaust port 32 thus venting the motor chambers I08, 68, 59, 52, 83, 93,I04 and I01, respectively, while a port I I I in said rotary valve iseffective to supply fluid at main reservoir pressure from the chamber 5to the pipe 23 and thence to the chamber 1I. As fluid under pressure isthus initially supplied to the chamber II, it will flow against theleft-hand face of piston 40 and the right-hand end of stem 65. The fluidunder pressure thus acting on piston 40 and stem 65, with chamber I01vented is effective to maintain the movable parts of the fluid motor inthe position in which they are shown in Fig. 1 and the device (notshown) connected to the piston rod 2 against movement due to exterthehandle I4 from position No. 1 to position As will be seen in Fig. 2,with the handle I4 in position No. 2, a cavity H2 in the rotary valve 5connects the pipes and passages 24, 25, 29, 21. 28 and 29 to the exhaustport 32 thus venting the chambers I08, 68, 59, 52, 83 and 93,respectively, while a port H3 in said rotary valve is effective tosupply fluid at main reservoir pressure from the chamber 5 to the pipes30, 3| and 23 and thence to the right and left-hand faces of pistons 98and 40.

Since the diameter of the stem 99 is greater than the diameter of thepiston rod 2, the effective area of the left-hand face of the piston 98is less than the effective area of the right-hand face of said piston.Since the area of piston 98 thus subjected to pressure of fluid inchamber I04 is greater than the area of the opposite face of piston 40,a diflerential in opposing forces is thereby established on said pistonswhich will move the two pistons toward the left-hand to a positiondefined by contact of piston 98 with retaining member I05. The area ofthe right-hand face of piston 40 being less than the area of theopposite face by the area of rod 2, a differential force is provided onsaid piston which urges same against the stem 99 to prevent over-travelof piston 40 when moved by piston 98, as just described, from positionNo. 1 to position No. 2.

It will be noted that it is not necessary to supply fluid under pressureto pipe 3! as above described when handle I4 is turned to position No. 2from position No. 1, since fluid under pressure supplied to pipes 30 and23 will establish the differential of pressures suflicient to movepistons 9B and 4D in the direction of thele-ft-hand. It is necessary,however, as will be later described, to supply fluid under pressure topipe 3! when handle I4 is turned from position No. 3 or some otherposition back to position No. 2, to move piston member 1! and 87 back tothe position in which they are shown in Fig. 1, if they do not alreadyoccupy this position.

To continue the movement of piston 40 in :the direction of theleft-hand, the operator will turn the handle Hi from position No. 2 toposition No. 3.

As will be seen in Fig. 2, with the handle M in position No. 3, a cavityll 14 in the rotary valve 8 connects the pipes and passages 24, 25, 26,21, 29, 30 and IN to the exhaust port 32 thus Venting the chambers H38,68, 59, 52, 93, I84 and IN, respectively, While a port I If; in saidrotary valve is effective to supply fluid at mainreservoir pressure fromthe chamber 5 to the pipes 28 and 23 and thence to the right-hand faceof piston member 17 and the left-hand face of piston 40.

A differential of forces will thereby be established by fluid underpressure in the chambers 83 and H acting on piston members i7 and 81which will move said piston members in the direction of the left-handuntil piston member 87 engages first the piston 98, the piston member 81after engaging piston 98 moving said piston and piston 49 againstpressure of fluid in chamber H acting on piston to until piston memberTl engages the stop surface 86.

With the pistons of the fluid motor "I in the position shown in Fig. 1,the distance from the left-hand end of piston member H to the stopsurface 86 is greater than the distance from the left-hand face ofpiston 98 to the retaining member I05. Therefore, when the piston member'1'! engages the stop surface 38, the piston '40 will occupy a positionto the left of the position it o'ccupied when the handle [4 was inposition No. '2.

To continue the movement of piston 40 in the direction of the left-hand,the operator will turn the handle Hi from position N o. 3 to positionNo. 4.

As will be seen in Fig. 2, with the handle 14 in position No. 4, acavity H1 in the rotary valve 8 will connect the pipes and passages 24,25, 26, 2'! and 29 to the exhaust port 32 thus venting the chambers I08,68, 59, 52 and 93, respectively, while a port H8 in said rotary valve iseffective to supply fluid at main reservoir pressure from the chamber 5to pipes 23, 28, 30 and 3| and thence to the right and left hand facesof pistons 40 and 98 and piston member 11.

The fluid under pressure supplied to chamber 83 through pipe 28 iseffective to maintain piston member 7? in engagement with the stopsurface 86.

Since, as has been hereinbefore explained, the effective area of theleft-hand face of the piston 98 is less than the effective area of theright-hand face of said piston, and the area of the right-hand face ofsaid piston is greater than the area of the left-hand face of piston 48,the fluid under pressure supplied to the right-hand face of piston 98and left-hand face of piston 40 establishes a differential in opposingforces on said pistons which will move the two pistons toward theleft-hand to a new position defined by contact of piston 98 withretaining member !85. As has been hereinbefore explained, the area ofthe right-hand face of piston 40 being less than the area of the op- 8prevent overtravel of piston in when moved by piston 98, as justdescribed.

It will be noted that it is not necessary to supply fluid under pressureto pipe 3| when handle I4 is turned to position No. 4 from position No.3 since fluid under pressure supplied to pipes and 23 will establish adifferential of forces on pistons 98 and 4B sufficient to move saidpistons in the direction of the left-hand. It is necessary, however, tosupply fluid under pressure to pipe 3| when handle 14 is turned fromposition No. 5, or some other position back to position No. 4 to movepiston member 81 into engagement with piston member ll if said pistonmember 87 is not already in engagement with piston member TI. This willbe apparent from the description of operation of the pistons and pistonmembers in moving to their other positions, which will be hereinafterdescribed.

When the piston members 1'! and 8] and pistons 98 and reach position No.4 described above, the piston 40 and piston rod 2 will have been movedin the direction of the left-hand from the position in which they areshown in Fig. 1, a distance equal to the distance from the lefthand endof piston member 11 to the stop surface SE shown in Fig. 1 plus thedistance from the left-hand of piston 98 to the right-hand end ofretaining member I05 when the piston 98 cccupies the position shown inFig. 1. In other words the distance that piston 40 and piston rod 2 aremoved in the direction of the left-hand, from the position in which theyare shown in Fig. 1, when handle [4 is moved to position No. 4, is equalto the sum of the distances they are moved when the handle 14 is movedto positions No. 2 and 3.

To continue the movement of piston 40 in the direction of the left-hand,the operator will turn the handle I4 from position No. 4 to position No.5.

As will be seen in Fig. 2, with the handle M in position No. 5, a cavityH9 in the rotary valve 8 connects the pipes and passa es 24, 25, 26, 21,28, 30 and 3| to the exhaust port 32 thus venting the chambers I08, 68,59, 52, 83, 104, and IE1, respectively, while a port I29 in said rotaryvalve is effective to supply fluid at main reservoir pressure from thechamber 5 to pipes 23 and 29 and thence to the left-hand face of piston40 and the right-hand face of piston member 87.

Since the area of piston member 81 thus subjected to pressure of fluidin chamber '93 is greater than the area of the opposite face of piston40, a differential in forces will thereby be established, which willmove piston member 87 into contact with piston 98 and then move pistons98 and 40 in the direction of the left-hand until piston member 81engages the stop surface 91.

During movement of the piston member 8''! and pistons 98 and 49 in thedirection of the lefthand, as just described, the left-hand face ofpiston 48 being subjected to fluid under pressure in chamber H urgespiston 40 against the stem 99 to prevent overtravel of piston when movedby piston member 81 and piston 98 from position N o. 4 to position No.5.

With the pistons of the fluid motor i in the position shown in Fig. 1,the distance from the left-hand end of piston member 87 to the stopsurface 9'! is greater than the distance from the left-hand end ofpiston member Ti to the stop surface 86 plus the distance from theleft-hand face of piston 98 to the retaining member H35. Therefore, whenthe piston member '87 engages '9 the stop surface 91', and the piston 98engages the piston member 8! at the right-hand end of counterbore 88,the piston 48 will occupy a position to the left of the position itoccupied when the handle I4 was in position No. 4.

To continue the movement of piston 49 in the direction of the left-hand,the operator will turn the handle I4 from position No. 5 to positionNo.6.

As will be seen in Fig. 2, with the handle I4 in position No. 6, acavity I2I in the rotary valve 8 connects the pipes and passages 24, 25,26, 21, 28 and SI to the exhaust port 32 thus venting the chambers I88,68, 59, 52, 83 and I81, respectively, while a port I22 in said rotaryvalve is effective to supply fluid at main reservoir pressure from thechamber 5 to pipes 23, 29 and 38, thence to the left-hand face of piston48, the right-hand face of piston member 81, and the right-hand face ofpiston 98.

The fluid under pressure supplied to chamber 93 through pipe 29 iseffective to maintain piston member 87 in engagement with the stopsurface 91'.

As has been hereinbefore explained, the fluid under pressure supplied tothe right-hand face of piston 98 and left-hand face of piston 48establishes a differential in opposing forces on said pistons which willmove the two pistons toward the left-hand to a position defined bycontact of piston 98 with retaining member I85. Overtravel of piston 48is prevented by fluid pressure acting on the left-hand face thereof ashas been hereinbefore explained.

When the piston member 87 and pistons 98 and 48 reach position No. 8described above, the piston 48 and piston rod 2 will have been moved inthe direction of the left-hand from the position in which they are shownin Fig. l, a distance equal to the distance from the left-hand end ofpiston member 81 to the stop surface 91 plus the distance fom theleft-hand end of piston 98 to the right-hand end of retaining member I85when the piston 98 occupies the position shown in Fig. 1. In otherwords, the distance that piston 48 and piston rod 2 are moved in thedirection of the left-hand from the position in which they are shown inFig. 1, when handle I4 is moved to position No. 6, is equal to the sumof the distances they are moved when the handle I4 is moved to positionsNos. 2 and 5.

To continue the movement of piston 48 in the direction of the left-hand,the operator will turn the handle I4 from position No. 6 to position No.'7.

As will be seen in Fig. 2, with the handle I4 in position No. '7, acavity I23 in the rotary valve 6 connects the pipes and passages 23, 21,28, 29 and 38 to the exhaust port 32 thus venting the chambers II, 52,83, 93 and I84, respectively, while a port I24 in said rotary valve iseffective to supply fluid at main reservoir pressure from the chamber 5to pipes 24, 25, 26 and 3| and thence to the right and left hand facesof piston 64, left-hand face of piston member 56, and right-hand face ofpiston 43.

The fluid under pressure thus effective on the left-hand face of pistonmember 56' will move said piston member in the direction ofthe'righthand until said piston member engages the stop surface 63, saidmember carrying with it the piston 84. At the same time as fluid underpressure is flowing to chamber 59 through pipe 26, fluid under pressureis also flowingto chamber 68 through pipe 25 and to chamber I88 throughpipe 24.

The effective area of the right-hand face of piston 64 is less than thearea of the left-hand face by an amount equal to the area of stem 65.Therefore, the fluid under pressure acting on the opposite faces ofpiston 64 is eifective to establish a differential in opposing forces onsaid piston which will move said piston relative to the piston member 59toward the right-hand to a position defined by contact of piston 64 withretaining member 69.

When the right-hand end of piston member 56 engages the stop surface 63and the righthand face of piston 84 engages the retaining member 69, theright-hand end of stem 65 will have been moved in the direction of therighthand from the position in which it is shown in Fig. l a distanceequal to the distance from the right-hand end of piston member 56 to thestop surface 63 plus the distance from the righthand face of piston 64to the retaining member 69 when said piston member and piston occupy theposition in which they are shown in Fig. 1.

When the piston member 55, the piston 64, and stem 65 are moved to theabove described posi-' tion, the end of stem 65 will be disposed in aposition to the left of the position, the piston 48 occupied when thehandle I4 was in position No.6.

The fluid under pressure supplied to chamber I81 through the pipe 3! iseffective to move the piston 48 in the direction of the left-hand untilthe left-hand face of said piston engages the end of stem 85, the pistonmembers I1 and 81 and piston 98 moving back to the position in whichthey are shown in Fig, 1 due to pressure of fluid in chamber I81.

Since fluid under pressure acting on the righthand face of piston 48must move sa d piston and piston rod 2 in the direction of the left-handagainst the load on said rod while the piston member 56 and piston 64move against no load, except friction, the piston member 56 and piston64 will move to their above described positions prior to movement of thepiston 48 to the position in which it engages the end of stem 65.Therefore, overtravel of piston 48 is prevented.

When the piston 48 engages the end of stem 64, said piston will occupy aposition No.7 which is to the left of the position it occupied when thehandle I4 was in position No. 6.

It will be noted that it is not necessary to supply fluid under pressureto pipe 24 when handle I4 is turned to position No. 7 from position No.6 since fluid under pressure supplied to chamber I88 at this time onlyacts in opposition to fluid under pressure supplied to chambers 68 and59. It is necessary, however, to supply fluid under pressure to chamberI88 when handle I4 is turned from position No. 11 back to position No. 7to effect movement of piston 48 and piston rod 2 in the direction of theright-hand from the position they occupy when the handle I4 is inposition No. 11. This will be more clearly understood from thehereinafter given description of position No.

To continue the movement of piston 48 in the direction of the left-hand,the operator will turn the 8handle I4 from position No. 7 to position Aswill be seen in Fig. 2, with the handle I4 in position No. 8, a cavityI25 in the rotary valve 8 connects the pipes and passages 23, 26, 28, 29and 38 to the exhaust port 32 thus venting the chambers II, 59, 83, 93and I84, respectively, while a port I26 in said rotary valve iseffective to supply fluid at main reservoir pressure from the cham-' 11her to pipes 24, 25, 2! and 3I, thence to the left and right hand facesof piston 64, left and right hand faces of piston member 49, andright-hand face of piston 40.

Since the area of the left-hand face of piston member 49 thus subjectedto pressure of fluid in chamber 52 is greater than the area of theopposite face by an amount equal to the area of stem 65, a differentialin opposing forces is thereby established on said piston which will movesame toward the right-hand to a position defined by contact with stopsurface 55.

Since fluid under pressure is supplied to chamber 68 through pipe inposition No. 8, as in position No. 7, said fluid under pressure Willmaintain the right-hand face of piston 64 in contact with retainingmember 69.

When handle I4 is moved to position No. 8, the chamber 56, which wascharged with fluid under pressure when handle I4 was in position No. '7,is vented to atmosphere through pipe 26 at the same time as fluid underpressure is suppliedto chamber I68 through pipe 24. Therefore, as thepressure in chamber 59 is reduced, the fluid under pressure in chamberI68 moves piston member 56 and piston 64 in the direction of theleft-hand until said piston member engages the piston member 49 at theleft-hand end of counterbore 50.

When the right-hand end of piston member 49 engages the stop surface 55,the left-hand end of piston member 56 engages the piston member 49 atthe left-hand end of counterbore 56, and the right-hand face of piston64 engages the retaining member 69, the right-hand end of stem 65, the

piston and the piston rod 2 will have been moved, in the. direction ofthe left-hand from the position they occupied when handle I4 was inposition No. 7, a distance equal to the depth of counterbore 44, or, inother words, a distance equal to the distance from the. right-hand endof piston member 56 to the stop surface 63 minus the distance from theright-hand end of piston member 49 to the stop surface when said pistonmembers occupy the position in which they are shown in Fig. 1.

The fluid under pressure supplied to chamber IOI through the pipe 3I iseffective to move the piston 46 in the direction ofv the left-hand asthe stem 65 moves in the direction of the left-hand in the mannerexplained above. Therefore, piston 49 maintains contact with theright-hand end of stem 64 in moving from position No. 7 to position No.8- and overtravel of piston 46 is prevented as in the precedingpositions.

To continue the movement of piston 46 in the. direction of theleft-hand, the operator will turn the handle. I4 from position No. 8 toposition No. 9.

As will be seen in Fig. 2, with the handle I4 in position No. 9, acavity I21 in the rotary valve 3 connects the pipes and passages 23, 26,21, 23, 29 and 36' to the exhaust port 32 thus venting the chambers 'II,59, 5'2, 83, 93 and I64, respectively, while a port I28 in said rotaryvalve is effective to supply fluid at main reservoir pressure from thechamber 5 to pipes 24, 25 and 3I thence to the left and right-hand facesof piston 64, and the righthand face of piston 46.

Since fluid under pressure is supplied to chamber 68 through pipe 25 inposition No. 9 as in positions No. '7 and 8, said fluid under pressurewill maintain the right-hand face of piston 64 in contact with retainingmember 69.

When handle I4 is moved to position No. 9, the chamber 52, which wascharged withv fluid under pressure with handle I4 in position No. 8, isvented to atmosphere at the same time as fluid under pressure issupplied to chamber I68 through pipe 24. Therefore, as the pressure inchamber 52 is reduced, the fluid under pressure in chamber I68 movespiston members 56 and 49 and piston 64 in the direction of the left-handuntil piston member 49 engages the end of casing section 35 at theleft-hand end of counterbore 48, the right-hand face of piston 64remaining in contact with the retaining member 69.

When the left-hand end of piston member 49 engages the end of casingsection 35 at the lefthand end of counterbore 48, with piston member 56in engagement with said piston member 49 at the left-hand end ofcounterbore 56, and piston 64 in engagement with retainin member 69, theright-hand end of stem 65 will have been moved in the direction of theleft-hand from the position it occupied when handle I4 was in positionNo. 8, a distance equal to the distance from the right-hand end ofpiston member 49 to the stop surface 55 when said piston member occupiesthe position in which it is shown in Fig. 1.

The fluid; under pressure supplied to chamber I61 through the pipe 3I iseffective to move the piston 46 in the direction of the left-hand as thestem 65 moves in the direction of the left-hand 1n the manner explainedabove. Therefore, piston 46 maintains contact with the right-hand end ofstem 64 in moving from position No. 8 to position No. 9 and overtravelof piston 46 is prevented as in the preceding positions.

To continue the movement of piston 46 in the direction of the left-hand,the operator will turn the handle I4 from position No. 9 to position No.10. As will be seen in Fig. 2, with the handle I4 in position No. 10', acavity I29 in the rotary valve It connects the pipes and passages 23,24, 25, 21, 28, 29 and 36 to the exhaust port 32 thus venting thechambers II, I68, 68, 52, 83. 93 and I64, respectively, while a port I36in said rotary valve is effective to supply fluid at main reservoirpressure from the chamber 5 to pipes 26 and 3|, thence to the left-handend of piston member 56 and the right-hand face of piston 46.

When handle I4 is moved to position No. 10, the chamber 68, which wascharged with fluid under pressure when handle I4 was in position No. 9,is vented to atmosphere through pipe 25 at the same time as fluid underpressure is supplied to chamber 59 through pipe 26. Therefore. fluidunder pressure acting on the left-hand face of piston. member 56 inchamber 59, and fluid under pressure acting On the right-hand face ofpiston 40 simultaneously moves the piston member 56 in the direction ofthe right-hand and the. pistons 64 and 40 in the direction of thelefthand until the piston member 56 engages the sto surface 63 and theleft-hand face of piston 64 engages the piston member 56 at theleft-hand end of counterbore 5'! in the piston member 56-.

When the right-hand end of piston member 56 engages the stop surface 63.and the left-hand face of piston; 64 engages the piston member 56 at theleft-hand end of counterbore 51, the righthand end of stem 65, thepiston 46, and piston rod 2 will have been moved, in the direction ofthe left-hand from the position they occupied when handle I4 was inposition No. 9, a distance equal to the distance'from theright-hand faceof piston 64 to the retaining member 69 minus the distance from theright-hand end of: piston member 56 to the stop surface 63 when saidpiston member and piston occupy the position in which they are shown inFig. l. 7

To continue the movement of piston 40 in the direction of the left-hand,the operator will turn the handle I4 from postion No. 10 to position No.11.

As will be seen in Fig. 2, with the handle I4 in position No. 11, acavity I3I in the rotary valve.

8 connects the pipes and passages 23, 24, 25, 26, 28, 29 and 30 to theexhaust port 32 thus venting the chambers II, I68, 68, 59, 83, 93 andI04, respectively, while a port I32 in said rotary valve is effective tosupply fluid at main reservoir pressure from the chamber to pipes 21 and3| thence to the left-hand face of piston member 49, and the right-handface of piston 46.

With the chamber 59 connected to atmosphere, and fluid under pressuresupplied to the left-hand face of piston member 49 and the right-handface of piston 40, as explained in the preceding paragraph, said fluidunder pressure will simultaneously move piston member 49 in thedirection of the right-hand until said piston member 49 engages stopsurface 55 and piston member 56, and pistons 64 and 46 in the directionof the lefthand until said piston member 56 engagesthe piston member 49at the left-hand end of counterbore 50 in said piston member 49.

When the right-hand end of piston member 49 engages the stop surface 55and the left-hand end of piston member 56 engages the piston member 49at the left-hand end of counterbore 50, with piston 64 in engagementwith piston member 56 and the left-hand face of piston 40 in engagementwith the right-hand end of stem 65, said piston 40 and piston rod 2 willhave been moved, in the direction of the left-hand from the positionthey occupied when handle I4 was in position No. 10, a distance equal tothe depth of counterbore 44, or in other words, a distance equal to thedistance from the right-hand end of piston member 56 to the stop surface63 minus the distance from the right-hand end of piston member 49 to thestop surface 55 when said piston members occupy the position in whichthey are shown in Fig. 1.

To continue the movement of piston 46 in the direction of the left-hand,the operator will turn the handle I4 from position No. 11 to positionNo. 12.

As will be seen in Fig. 2, with the handle I4 in position No. 12, acavity I 33 in the rotary valve 8 connects the pipes and passages 23,24, 25, 26, 21, 28, 29 and 39 to the exhaust port 32 thus venting thechambers II, I98, 68, 59, 52, 83, 93, and I04, respectively, while aport I34 in said rotary valve is efiective to supply fluid at mainreservoir pressure from the chamber 5 to pipe 3| thence to theright-hand face of piston 40.

When handle I4 is moved to position No. 12, the chamber 52, which wascharged with fluid under pressure when handle I4 was in position No. 11,is vented to atmosphere through pipe 21 at the same time as fluid underpressure is supplied to the right-hand face of piston 46. Therefore, thefluid under pressure acting on the right-hand face of piston 40 willmove said piston, piston rod 2, piston 64, and piston members 56 and 49in the direction of the left-hand until the piston member 49 engages thecasing section 35 at the left-hand end of counterbore 48 in whichposition piston 64 and piston members 49 and 56 are shown in Fig. 1.

When the left-hand end of piston member 56 engages the casing section 35at the left-hand end of counterbore 48, the right-hand end of stem 65,the piston 40 and piston rod 2 will have been. moved, in the directionof the left-hand, from the position they occupied when'handle I4 was inposition No. 11 a distance equal to the distance from the right-hand endof piston member 49 to the stop surface when said piston member 49occupies the position in which it is shown in Fig. 1.

When handle I4 is turned to position No. 12, the piston 40 and pistonrod 2 will be moved by pressure of fluid in chamber I0! to their extremeleft-hand positions in which the piston members 49 and 56 and piston 64occupy the position in which they are shown in Fig. l and the piston 40is moved into engagement with the right-hand end of stem 65.

With handle M in position No. 12, the operator may turn said handle toposition No. 13 to vent all fluid under pressure from the motor I, or,as will now be apparent, he may turn the handle [4 successively backthrough the previous eleven positions to move-the piston 49 and pistonrod 2 in steps back to the position in which they are shown in Fig. 1,or he may turn the handle I4 from any one of its positions to any otherof said positions and the piston 40 and piston rod 2 will be moved tothe corresponding position.

Summary It will now be seen that Ihave provided a fluid motor forpositively moving a device to any selected one of a multiple ofdifferent definite positions Without the possibility of said devicebeing moved beyond the desired position.

Having now described my invention, what I claim as new and desire tosecure by Letters Paten is:

1. A fluid motor comprising a casing having three bores, :a doubleacting power piston slidably mounted in one of said bores, threetelescopically arranged piston members mounted in each of the otherbores, three stops for each three telescopic piston members two of saidstops on said casing for limiting movement of the respective outer andintermediate piston members and the third of said stops on saidintermediate piston member for limiting movement of the respective innerpiston member relative to said intermediate piston member, said pistonmembers cooperating with said stops to provide at least twelve definitepositions of said power piston.

2. A fluid motor comprising three coaxially arranged casing sectionseach having a bore, a double acting power piston slidably mounted in thebore of the center casing sections, three telescopically arranged pistonmembers slidably mounted in each of the end casing sections, threechambers for each three telescopically arranged piston members the firstof said chambers formed between one of said end casing sections and theouter telescopic piston member, the second of said chambers formedbetween said outer telescopic piston member and the intermediatetelescopic piston member, and the third of said chambers r formedbetween said intermediate telescopic piston member and the innertelescopic piston member, three stops for each three telescopic pistonmembers two of said stops being carried by said center casing sectionfor limiting movement of said outer and intermediate piston members andthe third of said stops carried by said intermediate piston member forlimiting movement of said inner piston member, and a fluid pressurecommunication between each of said chambers and the exterior of saidcasing for conveying fluid 15 under pressure to said chambers" to movethe respective piston member into engagement with its respective stop tolimit movement of said power piston.

3. In combination, a fluid motor comprising three coaxially arranged.casing sections each having a. bore, a double actingv power pistonslid.-ably mounted in the bore in the center' casing section, two. piston stopmeans each comprising three telescopically arranged piston members each.having a diameter greater than the diam e'ter of said power piston,. oneof said piston stop means slidably mounted in eacnofi the other casingsections, a first fluid pressure communication extending: from each ofthe inner piston members through the adjacent intermediate and outerpiston members to the exterior of the respective casing section, a;second fluid pressure communication extending from: each: of the intermediate piston members through the adjacent outer piston member tothe exterior of the respective casing section, a third fluid pressurecommunication extending: from each of the outer piston members to theexterior of the respective casing section, a stopmember carried by thecenter casing section for each of the inter mediate and outer pistonmembers for limiting movement thereof in the direction of said powerpiston and another stop member carried by each of the intermediatepiston members for limiting movement of each. of the adjacent innerpi'szton members relative thereto, a manually operative control valvedevice operative: to a plu- 16 rality of positions to; in each position,supply fluid under pressure to one face and to release fluid underpressure from the opposite face of certain of said piston members toposition one or more of said piston members in a plurality of positionsto limit movement of said power piston to difierent positions, a pipeconnecting each of said fluid pressure communications to said controlvalve device for conveying fluid under pressure from said control valvedevice to the faces-- of said piston members to efiect movement thereofiinto engagement with said stops, and two'- pipes for conveying fluidunder pressure from said control valve to the respective faces of. saidpower piston to eflect movement thereof into engagement with one oi saidpiston members.

' WALLACE F. POORE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 11,866,669: Campbell May 26, 193122343009 Robinson Mar, 4, 1941 2,510,314 Jirsa June 6, 1950 2,524,488Stevens Oct. 3, I950 FOREIGN PATENTS Number Country Date 73,412Switzerland w Oct. 2, 1916 144 ,71? Austria Feb. 25-, 1936

